(57) An improvement is proposed in the performance of a mag­neto-optical recording medium having a laminar structure consist­ing of (a) a transparent substrate plate, (b) a first protecting dielec­tric layer, (c) a recording layer of, e.g., an alloy of a rare earth met­al and iron, cobalt or nickel, (d) a second protecting dielectric layer and (e) a metallic reflecting layer. The improvement consists in that the first and/or second protecting layers are formed from a bi­nary composition of SiN, SiO or AlN and a fluoride of a rare earth element in a specified molar proportion to have a good balance of the light transmission and refractive index in a relatively short wavelength of light. The magneto-optical recording medium is im­parted with greatly improved sensitivity and density of recording along with high stability against the attack by the atmospheric oxygen.